A month has passed since we saw the Sony Xperia XZ2 Premium on Geekbench running Android 9.0 Pie and now the update is finally rolling out. Screenshots from the System update menu The build number of the new software is 52.0.A.3.84 and interestingly enough, it's just 210MB big. Like the other Xperia phones that got the update last week, the XZ2 Premium won't be getting the gesture-based navigation that usually comes with the Pie, but you can benefit from Xperia XZ3's camera UI. Supposedly, it can also improve the overall camera quality. For now, we don't know what regions are...
Source: https://www.gsmarena.com/sony_xperia_xz2_premium_receiving_android_90_pie-news-34245.php